A 37-year-old man from Manchester, U.K., has been taken into custody after appearing in court charged with murdering his two young children, Sky News reported.
Petros Williams is accused of killing two-year-old son, Theo Molemohi, and four-year-old daughter, Yolanda.
Their bodies were discovered at Williams' apartment by their mother, Morongoe Molemohi, on Wednesday morning.
Williams was found collapsed at the scene and was arrested.
A post-mortem examination found the children had been strangled.
Molemohi, 30, who was recently separated from her husband, described her children before a Manchester court.
Calling her children a "fairy princess" and a "well-behaved young man," Molemohi said she "will take strength from their high energy and beautiful smiles."